Mechanomyographic signals generated during unfused tetani of single motor units in the rat medial gastrocnemius muscle
Mechanomyographic signals generated during unfused tetani of single motor units in the rat medial gastrocnemius muscle
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DOI：
10.1007/s004210100491
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发表时间：
2001-10-01
影响因子：
3
通讯作者：
Celichowski, J
中科院分区：
文献类型：
--
作者：
Bichler, E;Celichowski, J
本研究的目的是研究快速疲劳(FF)、快速抗疲劳(FR)和慢速(S)运动单位合并未融合性强直的机械性肌图(MMG)。分析破伤风期间MMG中的信号，对其进行不同程度的融合，以20、40和80赫兹三个频率电刺激诱发。未融合性破伤风的特点是张力振荡。未熔合收缩张力的每一次振荡都由MMG中的平行压力波信号反映。计算未融合性强直收缩的平均峰峰值、张力振荡幅度、张力增加速度和融合指数。随着刺激频率的增加，MMG的峰值张力增加，破伤风融合增加，未融合收缩的力振荡幅度减小，MMG信号的峰间幅度减小。此外，还发现MMG的幅度与所分析的未融合收缩的三个特性的幅度相关。结果表明，MMG中信号的幅度主要取决于强直收缩的动态特性，而收缩的静态分量(即张力振荡的水平)在MMG中没有反映出来。
The aim of this study was to investigate mechanomyograms (MMGs) accompanying unfused tetani of fast fatigable (FF), fast fatigue-resistant (FR) and slow (S) motor units. Signals in the MMG were analyzed during tetanus, which was fused to a variable degree, evoked by electrical stimulation at three frequencies: 20, 40 and 80 Hz. Unfused tetani were characterized by an oscillating tension. Each oscillation in the tension of an unfused contraction was reflected by a parallel pressure wave signal in the MMG. The mean peak-to-peak amplitude of signals in the MMG, the amplitude of oscillation in the tension, the velocity of the tension increase and the fusion index were calculated for the unfused tetanic contraction. The increase in stimulation frequency resulted in an increase in the peak tension, an increase in the fusion of the tetanus, a decrease in the amplitude of force oscillation in the unfused contraction and a decrease in the peak-to-peak amplitude of signals in the MMG. Moreover, it was found that the MMG amplitude was correlated with the amplitude of the three analyzed properties of the unfused contraction. It is concluded that the amplitude of signals in MMGs depends mainly on the dynamic properties of the tetanic contraction, whereas the static component of the contraction (i.e., the level around which the tension oscillates) is not reflected in the MMG.